1. Field of the Invention
The present invention relates to a method for inhibiting the growth of micro-organisms on surfaces by means of a composition comprising an amphoteric vinyl comb type co-polymer and an antimicrobial agent. The antimicrobial agent is controllably released from the amphoteric co-polymer over time thereby providing effective anti-microbial control.
Micro-organisms can be found on many inanimate and animate surfaces. The presence of such micro-organisms can result in unhygienic conditions in hospitals and medical environments, kitchens, bathrooms, toilets and in the preparation and packaging of foodstuffs leading to health risks and contamination.
Several anti-microbial agents exist which are effective against many of the virulent forms of micro-organisms found in the food and health-care environments. Unfortunately, the activity of such agents is insufficient in terms of providing a sustained, surface hygienic effect. This may be due to the high water solubility and/or lack of substantivity of the anti-microbial agent on a surface which means that the anti-microbial agent is readily displaced. There is therefore a requirement for an anti-microbial agent or an anti-microbial agent in combination with a delivery system which provides a high degree of anti-microbial kill over a sustained period of time.
2. Brief Description of Art
The literature describes various cases where micro-organisms and in particular bacterial fouling may cause damage or lead to contamination of surfaces including for example swimming pools, industrial pipes, architectural structures, ships hulls, hospital theatres, teeth and kitchen surfaces. Indeed, there have been many attempts and approaches to overcome the micro-biological problems associated especially with bacterial growth on inanimate and animate surfaces.
European Patent 0182523 describes how certain polymeric compositions are effective at preventing oral bacteria from colonisation on the surface of teeth. In UK Patent 2213721, an anti-staining composition comprising polymers with anti-bacterial agents were shown to be effective against bacteria found in an oral environment.
In European Patent 0232006, coating compositions comprising sulphonated polymers and a microbicide for use in marine environments were shown to have hydrolytic instability. In the above cases the coating of a polymer in an aqueous environment with or without microbicide was substantially erodable, thereby acting by means of a self-polishing effect, thereby reducing the ability of bacteria to colonise on the surface to be protected.
WO/02449 describes a process for the biocidal treatment of surfaces comprising high molecular weight grafted co-polymers.
However, none of the above documents describe an anti-microbial system which has both the ability to eliminate micro-organisms effectively and has a sustained, surface hygienic effect.
The term ‘sustained’ used hereinafter refers to an anti-microbial agent which is still active even after the surface to which the agent has been applied has been cleansed for example by wiping, rinsing or washing the surface.